Applications possess functional utilities that have important characteristics known as context. Context is defined as “the set of information which surrounds, and gives meaning to something else”. Examples of context can be found, for example, in presence applications, location applications, among others.
With regard to presence information, presence metadata provides meaning and the presence information is the basis of the context. The meaning is applied to or part of a particular function or a particular feature of a function within an application to establish an appropriate set of processing steps.
In one example, an instant message (IM) client application operable on a first user's mobile device may want functionality to establish whether other individuals or peers are reachable to permit the first user to initiate an IM chat session. It is also possible that within an IM client, functionalities are desired to establish a peer user status icon to represent a second user. In the first scenario, context relates to whether the second user is reachable to initiate a chat. In the second scenario, the first user's IM client discriminates and derives a status icon based on the second user's status and availability to display the correct status icon, indicia or avatar. In the context of the IM client, reachability as it relates to peer status icon feature may not be relevant, whereas reachability is helpful for facilitating the initiated chat function.
The above demonstrates, in a presence environment, that context plays a significant role in how an individual's presence information may be computed to derive presence related aspects, including reachability, availability, among others. As will be appreciated, context also applies in other scenarios besides presence.
A presence service captures presence information from one or more presence sources. Once this data is collected, a presence service composes the captured metadata and distributes a raw presence metadata document to authorized watchers. The OMA-Presence service platform is a demonstrative example of a presence service. The OMA-Presence enabler outlines, in very detailed written form, semantics and policy related to the publication and consumption of presence information.